The relatively new breed of malware known as "ransomware" works by encrypting files on an infected computer and issuing a demand for payment in Bitcoins to unencrypt them before a deadline, after which the price skyrockets.

Some victims have reported that despite paying the fee their files have been crunched anyway, and early attempts to disinfect machines have tripped booby traps that caused file destruction.

Up to now, the ransom has been two Bitcoins, but as exchange rates continue to soar that would put the extortion fee at nearly £900 at time of going to press. Newly infected machines, however, are only being asked for half a bitcoin, which is still a hefty £200+, rising to 4.5 Bitcoins, or over £2,000, after 72 hours.

So is this some act of Christmas charity from the criminal underworld?

No, not a bit. The truth is that personal data, like Bitcoins, has a price, and the hyperinflation of Bitcoins means they have exceeded the value of the average user's personal data.

The criminals have therefore had to rethink their strategy as, it would seem, £900 was a bridge too far to spend for retrieving family photos and old letters to the Radio Times.

As security companies continue to look for effective protection against ransomware, the usual advice still applies. Don't open attachments or click on links sent by people you don't know, have anti-virus software installed, and make sure it's up to date. Lack of common sense could still cost you £200. µ